diff --git a/actions/create_crush_rule.py b/actions/create_crush_rule.py
index 5fea57ba..207b4f4f 100755
--- a/actions/create_crush_rule.py
+++ b/actions/create_crush_rule.py
@@ -41,5 +41,6 @@ def create_crush_rule():
     except subprocess.CalledProcessError as e:
         hookenv.action_fail(str(e))
 
+
 if __name__ == '__main__':
     create_crush_rule()
diff --git a/actions/create_erasure_profile.py b/actions/create_erasure_profile.py
index 1cee8f3f..5306baa6 100755
--- a/actions/create_erasure_profile.py
+++ b/actions/create_erasure_profile.py
@@ -63,7 +63,7 @@ def make_erasure_profile():
             action_fail("Create erasure profile failed with "
                         "message: {}".format(str(e)))
     elif plugin == "lrc":
-        l = action_get("locality-chunks")
+        locality_chunks = action_get("locality-chunks")
         crush_locality = action_get('crush-locality')
         try:
             create_erasure_profile(service='admin',
@@ -71,7 +71,7 @@ def make_erasure_profile():
                                    profile_name=name,
                                    data_chunks=k,
                                    coding_chunks=m,
-                                   locality=l,
+                                   locality=locality_chunks,
                                    crush_locality=crush_locality,
                                    failure_domain=failure_domain,
                                    device_class=device_class)
diff --git a/actions/security_checklist.py b/actions/security_checklist.py
index 7afb3c1e..23b1caf1 100755
--- a/actions/security_checklist.py
+++ b/actions/security_checklist.py
@@ -42,5 +42,6 @@ def main():
     }
     return audits.action_parse_results(audits.run(config))
 
+
 if __name__ == "__main__":
     sys.exit(main())
diff --git a/files/nagios/check_ceph_status.py b/files/nagios/check_ceph_status.py
index 844e7f2f..2f49b23b 100755
--- a/files/nagios/check_ceph_status.py
+++ b/files/nagios/check_ceph_status.py
@@ -291,7 +291,7 @@ def main(args):
     EXIT_CODES = {'ok': 0, 'warning': 1, 'critical': 2, 'unknown': 3}
     exitcode = 'ok'
     try:
-        msg = check_ceph_status(args)
+        check_ceph_status(args)
     except UnknownError as msg:
         print(msg)
         exitcode = 'unknown'
@@ -301,7 +301,7 @@ def main(args):
     except WarnError as msg:
         print(msg)
         exitcode = 'warning'
-    except:
+    except Exception:
         print("%s raised unknown exception '%s'" % ('check_ceph_status',
                                                     sys.exc_info()[0]))
         print('=' * 60)
diff --git a/hooks/ceph_hooks.py b/hooks/ceph_hooks.py
index 1e45482c..3bda8f21 100755
--- a/hooks/ceph_hooks.py
+++ b/hooks/ceph_hooks.py
@@ -293,9 +293,9 @@ def config_changed():
     # unconditionally verify that the fsid and monitor-secret are set now
     # otherwise we exit until a leader does this.
     if leader_get('fsid') is None or leader_get('monitor-secret') is None:
-            log('still waiting for leader to setup keys')
-            status_set('waiting', 'Waiting for leader to setup keys')
-            return
+        log('still waiting for leader to setup keys')
+        status_set('waiting', 'Waiting for leader to setup keys')
+        return
 
     emit_cephconf()
 
diff --git a/test-requirements.txt b/test-requirements.txt
index 7d9c2587..44b50231 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -10,7 +10,7 @@
 charm-tools>=2.4.4
 requests>=2.18.4
 mock>=1.2
-flake8>=2.2.4,<=2.4.1
+flake8>=2.2.4
 stestr>=2.2.0
 coverage>=4.5.2
 pyudev              # for ceph-* charm unit tests (need to fix the ceph-* charm unit tests/mocking)
diff --git a/tox.ini b/tox.ini
index b835733a..8080ba6d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -116,5 +116,5 @@ commands =
     functest-run-suite --keep-model --bundle {posargs}
 
 [flake8]
-ignore = E402,E226
+ignore = E402,E226,W504
 exclude = */charmhelpers
diff --git a/unit_tests/test_ceph_ops.py b/unit_tests/test_ceph_ops.py
index c2e1e917..145aaf92 100644
--- a/unit_tests/test_ceph_ops.py
+++ b/unit_tests/test_ceph_ops.py
@@ -15,7 +15,7 @@
 import json
 import unittest
 
-from mock import (
+from unittest.mock import (
     call,
     patch,
 )